1,720,957 research outputs found
Bridging the Gap of Scales: A Micro-to Macroscale Study of the Tumor Microenvironment and Quantitative Imaging Features in Pancreatic Cancer
No full textThe field of Radiomics aims to extract quantitative features from medical images. To date, hundreds of Radiomics studies have been published, claiming that these quantitative features have clinical merit with the specific claim that a single number derived from medical images can be prognostic or diagnostic.
The aim of this research is to investigate what, if any, factors may be influencing these numbers. The underlying hypothesis is that select attenuation based textural features are sensitive to the biological structure of a tumor and its microenvironment. An attempt is made to study whether these features correlate with pathology-based characteristics of pancreatic tumors and how these features translate to much lower-resolution clinical CT images.
The approach used digitized pathology images and advanced image analysis techniques. Select features look promising for characterizing underlying pathology however, more comprehensive study is required to rigorously explore the aforementioned research aim. Hence the exploration continues…M.Sc
Signals in the Spread: Quantitative Imaging and Tumor Heterogeneity in Metastatic Cancer
Get PDFRadiomics is an emerging field that transforms standard medical imaging into quantitative data, offering the potential to non-invasively characterize tumor biology and predict clinical outcomes. However, most radiomic studies adhere to a “one patient, one lesion” paradigm, which overlooks the biological and spatial heterogeneity that defines multi-metastatic disease. This thesis proposes a new framework for radiomic analysis that explicitly embraces lesion-level variability to improve patient assessment in advanced cancers.
The work begins with a systematic benchmarking of ten multi-lesion feature aggregation strategies across three datasets representing regional, organ-confined, and widespread metastatic disease. Results demonstrate that no single method performs optimally across all contexts, underscoring the need for task-specific modeling approaches. Building on this, a novel imaging-derived metric—Measured Intrapatient Radiomic Variability (MIRV)—is introduced to quantify intertumor heterogeneity. In a cohort of soft-tissue sarcoma patients, MIRV was associated with volumetric response variability, ctDNA positivity, and survival outcomes, suggesting its potential as a non-invasive biomarker of treatment heterogeneity.
The thesis then shifts toward predictive modeling, developing lesion-specific classifiers to forecast treatment response at the level of individual pulmonary metastases. Using radiomic features from leiomyosarcoma patients, these models outperformed volume-based predictors and revealed the peritumoral region as a key source of biological signal. In a secondary analysis, the same modeling framework was repurposed to explore radiomic signatures associated with tumor hypoxia. By leveraging the design of the SARC021 trial and validating against an independent dataset, preliminary evidence is presented suggesting that radiomics may capture microenvironmental features relevant to hypoxia-driven treatment response.
Collectively, these studies contribute new tools, biomarkers, and modeling strategies that reposition radiomics as a system-level approach capable of capturing the spatial and biological complexity of multi-metastatic disease. The findings support a more nuanced, lesion-informed vision for precision oncology and offer a foundation for both clinical application and biological discovery.Ph.D
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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